The present invention relates to a refractory sagger for receiving raw ceramics or mosaic tiles to be burned, and more particularly to an improved refractory sagger of which uniform thermal expansion of the whole sagger under heating can be obtained so that cracking is rarely happened in the sagger even at sudden cooling or heating.
Although conventional sagger is primarily made of cordierite (2 Mg 0.2 Al.sub.2 O.sub.3.5SiO.sub.2) which exhibits a low expansion coefficient, crack will be produced in the sagger at sudden cooling or heating. Once there is a crack in the sagger and the sagger has been used several times, the sagger will be broken into pieces, and becomes a waste. Normally, a sagger can only be used for about 40 times. In addition, since the saggers are closely stacked in the kilns during burning, it is difficult to separate the stacked saggers away from each other without the aid of special tools after they are moved out from the kilns and have been cooled.